Perfumes find nowdays an extremely broad utilisation For example, cosmetic preparations, soaps, detergents and household materials in general represent the most currently perfumed articles found on the market. New types of materials liable to be perfumed, and thus rendered commercially more attractive, are constantly offered to the consumer Materials as varied as wax, paper, cardboard, synthetic resins, plastic or even metal are often considered suitable supports destined to incorporate perfumes or various volatile substances such as insecticides or bactericides.
Gypsum can also be taken into consideration for the very same purpose. Its use as carrier for perfumes was suggested in the past and the preparation of perfumed gypsum articles was already described [see F. Winter, "Handbuch der gesamten Parfumerie und Kosmetic," Springer Verlag, Vienna 1952, p, 288]. Hitherto, however, the manufacture of perfumed gypsum articles was not developed industrially.
This fact is rather surprising in view of the fact that:
Gypsum is an extremely cheap and readily available material; PA0 The manufacture of gypsum, which consists simply in mixing plaster and water in adequate proportions, does not necessitate complex apparatus or expensive processes; PA0 The perfume incorporation into the gypsum mass can be effected by simply impregnating the gypsum article with a diluted perfume, e.g., an alcoholic solution thereof; or PA0 The said incorporation can also be carried out, in accordance with the above cited literature, by mixing the required amount of perfume with the plaster-water mixture. PA0 phenylethyl alcohol: strongly hydrophile PA0 diethyl phthalate : strongly lipophile and PA0 isobornyl acetate : hydrophile/lipophile
The first incorporation mode hereinabove described is however unsatisfactory as the proportion of incorporated perfume cannot be precisely measured and perfume cannot be homogeneously distributed in the gypsum mass. The said process moreover is relatively slow and the proportion of incorporated perfume does not exceed 3 to 5 % of the total weight of the perfumed material.
The second of the above mentioned incorporation modes is also unsatisfactory as shown by the following investigation. In order to determine the possible feasibility of the said process it was made use of model substances, these being chosen according to their widespread occurrence as ingredients in perfume compositions and their more or less pronounced lipophilicity or hydrophilicity.
The following three compounds were used as models:
The obtained results -- see Test No. 1 -- clearly show that, in the three cases, the desired ingredient could be easily incorporated into the gypsum mass in a proportion of up to 5 % (parts by weight). Higher proportions cannot be incorporated, the mass "sweats" and presents an irregular texture.